1. Field of the Invention
The present invention relates to a current measuring apparatus and a testing method. More particularly, the present invention relates to a current measuring apparatus for measuring a power supply current received by an electronic device.
2. Description of the Related Art
With regard to an electronic device such as a CMOS semiconductor, a power supply current largely varies when an internal circuit operates. Further, conventionally, a voltage generating circuit in which variation in voltage applied to a load is small during an operation characteristics testing of an electronic device is known (for example, see Japanese Patent Application Laid-Open No. 1995-333249 (pages 2 to 4 and FIGS. 1 to 5)).
As a technique for micronizing an electronic device is improved, an operation speed is increased, an operation voltage is decreased, and an allowable range of variation in power supply voltage is lowered. Thus, a testing apparatus for testing the electronic device requires a power supply apparatus of higher accuracy.